Discoverability of the Roadmap

[MevenBertrand]

While it is currently easy to discover shiny bits about Rocq's past (ACM award, cool projects, big name university/companies using it, etc.), it is comparatively quite hard to find anything about Rocq's future.

In particular, the roadmap, which I guess is the main "document" here, is quite hard to discover (I was on the site looking for it and it took me a good couple minutes to find it knowing what I was looking for, and being sure it was there). As far as I can tell, it can be found in the following ways, both of which are somewhat unnatural:

• when going to the "Why Rocq?" page, there is a "Future" section (very short and somewhat buried between the long detailed list of features of Rocq and the bibliography), with a link to the roadmap.
• under "About Rocq" in the footer.

I'm not sure how to make it more discoverable, but maybe moving this "Future" section from "Why Rocq" to "About Rocq", possibly with a small paragraph outlining the vision + a link to the longer roadmap, would at least help? I don't know how prominent the roadmap should be. I can try to make a PR to do this if this seems like a good way to go.

[Zimmi48]

Whether we keep this section "Future" on the "Why Rocq?" page or move it to "About Rocq", we should add an icon linking to it from the top of the page.